Hydroconversion process of residuum oils

ABSTRACT

In processing high metals Venezuelan residuum, higher conversion of the 975*F plus fraction and improved operability can be obtained by maintaining a high catalyst addition rate to obtain reduced metals loading on the catalyst; it being determined that for a macroporous catalyst there is a limiting factor of metals deposition.

United States Patent Johnson et al.

HYDROCONVERSION PROCESS OF RESIDUUM OILS Assignee:

Filed:

Inventors: Axel R. Johnson, North Babylon;

Ronald H. Wolk, Trenton, both of N.J.; Seymour B. Alpert, Calif.

York, NY.

Sept. 13, 1973 Appl. No.: 397,071

abandoned.

U.S. Cl 208/108, 208/48 R, 208/112,

Int. Cl Cl0g 13/02, ClOg 9/16, BOlj 11/74 Los Altos,

Hydrocarbon Research, Inc., New

Field of Search 208/108, 112, 164, 251 H Cotolyst in 54 22 i, SolidsLevel 3 Reactor IBJIQF 1 Distributor? Plate 2o 1. 56

Cotolyst Feed gogolyst no -16 Hydrogen Mar. 11, 1975 [56] ReferencesCited UNITED STATES PATENTS 3,183,179 5/1965 Schuman l208/97 3,321,3935/1967 Schuman et a1. 208/10 3,547,809 12/1970 Ehrlich et al. 208/1433,553,106 l/197l Hamilton et a1. 208/251 H 3,622,500 1l/1971 Alpert eta1 208/111 3,819,509 6/1974 Wolk et a1. 208/216 Primary E.mminerDelbertE. Gantz Assistant Examiner-G. E. Schmitkons 2 Claims, 1 Drawing FigureVopor Catalyst in Liquid Level46 K/Trop Troy40 LlqUld Product (ToFractionation) Solids Level 1.

Distributor Plate 20 Cotoiyst Out Hydrogen PiiTENTED l l 75 Catalyst inFIG.

Vapor Catalyst in Liquid Level46 Trap Troy40 (To Fractionation) 42 r-Reactor 34 Distributor Plate 20 Catalyst Out Hydrogen 1 HYDROCONVERSIONPROCESS OF RESIDUUM OILS RELATED APPLICATION This is a continuation ofapplication Ser. No. 210,436, filed Dec. 21, 1971, and now abandoned.

BACKGROUND OF THE INVENTION The ebullated bed system described byJohanson in US. Reissue Pat. No. 25,770 has proved successful inhydrogenation, including hydrocracking and hydrodesulfurization, of awide variety of petroleum stocks. The advantages of high throughput,uniform temperature, low pressure drop and non-plugging characteristicshave been of great benefit to residuum processors. Liquid phaseconditions assure good catalyst contact with no substantial attrition.

ln processing vacuum residuum, such as Lagunillas, which contain inexcess of 500 ppm of vanadium, conversion was limited to about 50percent of the feed boiling above 975 F to lower boiling products in anonreplacement catalyst system. The high metals levels and highasphaltene content of Venezuelan residuum makes them difficult toconvert due to the rapid poisoning of catalyst. This results in a shortonstream time and, therefore, low conversion rates are obtained. As theamount of metals deposition on the catalyst increases the residuumbegins to coke in the reactor. The coking then causes the rapiddefluidization of the catalyst bed and this requires that the reactor bethen shut down. However, a catalyst replacement reactor system utilizinga catalyst replacement rate such that not more than about 23 percent ofvanadium was deposited on the catalyst showed long term successfuloperations even in the 70-80 percent conversion range.

SUMMARY OF THE INVENTION A system for obtaining in excess of a 70percent conversion of the 975 F plus fraction in high metals residuumsis disclosed using an ebullated bed reactor system. This system operatesby replacing the demetalization catalyst at a rate sufficient to limitvanadium deposition, thereby assuring continuous operability. The pro--cess for this invention is carried out at temperatures from 750 to 850F, pressures of 1,000 to 3,000 psig, space velocity of 0.2 to 2.0 V/hr/V (volume of feed per hour per volume of reactor) and a hydrogencirculation of 4,000 to l0,000 SCF of hydrogen per barrel of liquidproduct.

DESCRIPTION OF THE DRAWING The drawing is a schematic drawing of thepreferred embodiment of the process for the hydroconversion of highmetals content residua using a continuous demetalization catalystreplacement.

PREFERRED FORM OF EMBODIMENT may have a liquid distributor andcatalystsupport 20 so that the liquid and gas passing upwardly throughthe reactor 18 will tend to place the catalyst in random motion in theliquid.

The catalyst particle size range isusually ofa narrow size range foruniform expansion and random motion of the catalyst bed under controlledliquid and gas flow conditions. While the overall range of sizes thatcan be used is usually between 3 and 325 mesh (USS), a once throughoperation uses catalyst in the 60 to 325 mesh range with a liquidvelocity in the order of l to l0 gallons per minute per square foot ofhorizontal reaction space. Alternatively. larger catalyst, usually inthe 3 to 60 mesh size, can be used by adequate recycle of oil to providefrom about 10 to 60 gallons total liquid velocity per minutes per squarefoot of horizontal reactor space. The lifting effect of the hydrogen andoil are factors in the buoyancy of the catalyst.

High metals containing residua are considered heavy hydrocarbon oils.Such oils are most preferably hydrogenated with the use of catalyticmacroporous microspheres. These macroporous microspheres are composed ofplatinum, palladium, molybdenum, nickel or cobalt and the oxides orsulfides thereof or mixtures thereof supported on an alumina or silicacarrier or mixtures thereof as a carrier.

A macroporous microsphere catalyst according to this invention should beofa type and fall within a given size range as hereinbefore described.At the same time the macroporous microspheres have a pore volume of fromabout 0.10 cc/g to 0.60 cc/g comprising pores larger than 250A and apore volume of from about 0.30 cc/g to 0.50 cc/g comprising pores with adiameter of less than 250A. The total pore volume of the macroporousmicrospheres is between about 0.40 cc/g and about 1.10 cc/g. A preferredmacroporous microsphere catalyst would have a pore volume of from about0.2 to about 0.4 cc/g in pores with a diameter larger than 250A and apore volume from about 0.35 to about 0.45 cc/g in pores with a diameterofless than 250A and the total pore volume is between about 0.55 andabout 0.85 cc/g.

The macroporous microspheres have an average size such that weightpercent fall within a narrow size range and are ebullated by the upwardflow of oil and hydrogen through the reactor during hydroconversion. Thepore volume of the microspheres is critical as there must be apenetration of the hydrocarbon oil into the catalyst for at least a 3percent gain in weight. These microspheres are more specificallydisclosed in US. Pat. No. 3,622,500.

By the control of the microspherical catalyst particle size and densityand the liquid and gas velocities and taking into account the viscosityof the liquid under the operating conditions, the catalyst bed may beexpanded to have a definite solids level or interface indicated at 22 inthe liquid. The settled or static level of the catalyst is considerablylower than level 22. Normally, bed expansion should be at least 10percent and seldom over 300 percent of the static level.

The entire effluent is removed overhead at 24 and passed with suchhydrogen as may be required from line 32 into the second stage reactor34. This reactor is similar to the first stage reactor except that avapor separating space 36 is provided at the top. The vapors.substantially solids-free and liquid-free are removed at 38 and a liquidis removed over trap tray 40 through line 42. The upper solids level isindicated at 44 and the upper liquid level is indicated at 46.

While we have shown microspherical catalyst addi-:

up on catalyst. Therefore, 80 percent of vanadium ends up on catalyst. 4

1 While we have shown and described the preferred form of embodiment ofour invention, it will be appar-- 'ent that modifications may be madethereto without departing from the scope and spirit of the descriptionherein and of the claims appended hereinafter.

TABLE I I ll III IV FEED A* A A B* 0* API 4.0 4.0 v 4.0 l8 8 71 S 2.752.75 2.75 2.2 2.7 ppm V 535 535 535 200 570 Vol. 71 975F+ 75 75 75 50 89OPERATING CONDITIONS Temperature "F 830 840 830 825 820 Pressure psigCirculation 2250 2250 2250 2000 2000 H SCF/Bbl 5000 9000 5000 6000 6000Space Velocity V,/hr/V 0.6 0.5 0.6 0.5 0.4 CONVERSION** 72% 81% 7371 75%707:

Cat. Rate No./bbl. 0.36 0.36 0.l8 0.18 0.18 Vanadium on Spent Catalyst2O 21 8 23 Reactor Operability Satisfac- Satisfac- Coked Satisfac- Cokedtory tory tory C is Tia Juana V uum Bottoms.

"Conversion is dlsappearance of 975F plus material.

al., U.S. Pat. No. 3,547,809. The catalyst is added and removed at ahigh rate in the range of 0.2 to 0.5 lbs. of catalyst per barrel of feedoil so as to maintain the percent vanadium on the spent microsphericalcatalyst at less than 23 percent. Under these conditions the reactoroperates without defluidization or coking.

In a reactor system of this type, the vapor overhead 38 is largerlyhydrogen which may be purified by conventional means and after beingappropriately reheated and recompressed, can be recyled to the hydrogenfeed l n @2219 .32 .t21 2s1sa9 9r Although it is preferable tohydrogenate the feeds in a two stage system, a single stage is alsosuitable.

Table I shows the results of five operations for the hydrogenation ofheavy metals containing residuum using macroporous microspheres as thecatalyst. From the results it can be seen that the microsphericalcatalyst must be added and removed at a rate such that the spentcatalyst has less than 23 percent vanadium deposited on it. In thismanner at least 70 percent conversion of the feed is maintained withoutthe defluidization and coking of the microspherical catalyst bed takingplace.

Above 70 percent conversion. 85 percent of vanadium in the feed isremoved. 94 percent of which ends We claim:

1. In a process for the continuous hydrogenation of a Lagunillas vacuumbottoms having in excess of 500 ppm of metals from the group of vanadiumand nickel wherein the residuum and hydrogen are passed upwardly througha reaction zone containing a macropt rous microspherical particulatecatalyst being closely sized within the range of 60 to 325 U.S. Standardmesh at a rate to place the microspherical catalyst in random motion inthe liquid without substantial carryover from I the reaction zone andwherein the operating conditions are within a pressure range of 1,000 to3,000 P316, and a temperature range of 750 to 850F and a liquid spacevelocity of 0.2 to 2.0 V,/hr/V, such as to maintain conversion of atleast 80 percent of the portion of the residuum boiling above 975F tomaterial boiling below 975F wherein the improvement comprises:

adding said catalyst to and removing said catalyst from the reactionzone at a rate between 0.2 and 0.5 pounds of catalyst per barrel of feedoil such that the percent of vanadium on the spent catalyst is less than23 percent. 2. The process of claim 1 wherein the catalyst addition andwithdrawal rate is between 0.4 and 0.5 pounds of catalyst per barrel offeed oil.

1. IN A PROCESS FOR THE CONTINUOUS HYDROGENATION OF A LAGUNILLAS VACUUMBOTTOMS HAVING IN EXCESS OF 500 PPM OF METALS FROM THE GROUP OF VANADIUMAND NICKEL WHEREIN THE RESIDUUM AND HYDROGEN ARE PASSED WARDLY THROUGH AREACTION ZONE CONTAINING A MACROPOROUS MICROSPHERICAL PARTICULATECATALYST BEING CLOSELY SIZED WITHIN THE RANGE OF 60 TO 325 U.S. STANDARDMESH AT A RATE TO PLACE THE MICROSPHERICAL CATALYST IN RANDOM MOTION INTHE LIQUID WITHOUT SUBSTANTIAL CARRYOVER FROM THE REACTION ZONE ANDWHEREIN THE OPERATING CONDITIONS ARE WITHIN A PRESSURE RANGE OF 1,000 TO3,000 PSIG, AND TEMPERATURE RANGE OF 750* TO 850*F AND A LIQUID SPACEVELOCITY OF OF 0.2 TO 2.0 VF/HR/VR SUCH AS A TO MAINTAIN CONVERSION OFAT LEAST 80 PERCENT OF THE PORTION OF THE RESIDUUM BOILING ABOVE 975*FTO MATERIAL BOILING BELOW 975*F WHEREIN THE IMPROVEMENT COMPRISES:ADDING SAID CATALYST TO AND REMOVING SAID CATALYST FROM THE REACTIONZONE AT A RATE WHEREIN 0.2 AND 0.5 POUNDS OF CATALYST PER BARREL OF FEEDOIL SUCH THAT THE PRECENT OF VANADIUM ON THE SPENT CATALYST IS LESS THAN23 PERCENT.
 1. In a process for the continuous hydrogenation of aLagunillas vacuum bottoms having in excess of 500 ppm of metals from thegroup of vanadium and nickel wherein the residuum and hydrogen arepassed upwardly through a reaction zone containing a macroporousmicrospherical particulate catalyst being closely sized within the rangeof 60 to 325 U.S. Standard mesh at a rate to place the microsphericalcatalyst in random motion in the liquid without substantial carryoverfrom the reaction zone and wherein the operating conditions are within apressure range of 1,000 to 3,000 PSIG, and a temperature range of 750*to 850*F and a liquid space velocity of 0.2 to 2.0 Vf/hr/Vr such as tomaintain conversion of at least 80 percent of the portion of theresIduum boiling above 975*F to material boiling below 975*F wherein theimprovement comprises: adding said catalyst to and removing saidcatalyst from the reaction zone at a rate between 0.2 and 0.5 pounds ofcatalyst per barrel of feed oil such that the percent of vanadium on thespent catalyst is less than 23 percent.